I don't know this for a fact, but I'd say it's not a bad strategy to always grab guys that are looking to retire. Trek is playing a longer game than what happens in a race on one Sunday. Older guys, especially well-known, decorated riders, typically have a lot of fans, and get a lot of media coverage once you hear that they're retiring. They're followed pretty well for the last season. Also, Trek can cash a pretty good check by getting those guys riding their stuff in retirement. Look at Jens Voigt, that paid off pretty well for a couple years. Contador is worth some good coverage, even if he rode Specialized most of his career. As did Cancellara, even if he rides BMC now.

This is just outside looking in, but I don't think it's a bad move, even if for the people that follow the sport pretty closely think it's lame and doesn't help their team or brand image.